They certainly do, and it does mean that there are a number of them and that they are being spread a lot. It doesn't necessarily means that there are hundreds of different ones, though. For example, there are a number of rumours about the Madeleine McCann case at the moment- she was murdered, accidentally overdosed, etc. You could say that rumours abound there, though there are only a handful, with minor variations, but they are being discussed a lot.
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